The present invention relates generally to the field of esophageal prosthetics. More specifically, a prosthesis delivery device is disclosed for submucosal insertion of a prosthetic bulking device.
Gastroesophageal reflux is a physical condition in which stomach acids reflux, or flow back from the stomach into the esophagus. Frequent reflux episodes (two or more times per week), may result in a more severe problem known as gastroesophageal reflux disease (GERD). Gastroesophageal reflux disease is the most common form of dyspepsia, being present in approximately 40% of adults in the United States on an intermittent basis and some 10% on a daily basis.
Dyspepsia, or heartburn, is defined as a burning sensation or discomfort behind the breastbone or sternum and is the most common symptom of GERD. Other symptoms of GERD include dysphasia, odynophagia, hemorrhage, water brash, and pulmonary manifestations such as asthma, coughing or intermittent wheezing due to acid aspiration. Dyspepsia may also mimic the symptoms of a myocardial infarction or severe angina pectoris. Many factors are believed to contribute to the onset of GERD including transient lower esophageal sphincter relaxations, decreased LES resting tone, delayed stomach emptying, and an ineffective esophageal clearance. Many in the field agree, however, that the primary cause of GERD is the lack of competency of the lower esophageal sphincter.
The lower esophageal sphincter, or valve, is comprised of smooth muscle located at the gastroesophageal (GE) junction and functions to allow food and liquid to pass into the stomach but prevent regurgitation of stomach contents. At rest, the LES maintains a high-pressure zone between 10 and 30 mm Hg above intragastric pressure. Upon deglutition, the LES relaxes before the esophagus contracts, allowing food to pass through into the stomach. After food passes into the stomach, the LES contracts to prevent the stomach contents and acids from regurgitating into the esophagus. The mechanism of LES opening and closing is influenced by innervation via the vagus nerve and hormonal control of gastrin and possibly other gastrointestinal hormones.
The severity of GERD varies from patient to patient and in extreme cases complications including esophageal erosion, esophageal ulcers, and esophageal stricture are observed. Esophageal stricture is a serious condition which results from prolonged exposure of the esophageal mucosa to acid reflux. The most common clinical manifestation of stricture is dysphasia. Unlike dysphasia from non-strictured esophageal reflux, dysphasia caused by stricture is progressive in that the size of a bolus which can pass into the stomach progressively becomes smaller. In addition to esophageal erosion and ulceration, prolonged exposure of the esophageal mucosa to stomach acid can lead to a condition known as Barrett""s Esophagus. Barrett""s Esophagus is an esophageal disorder that is characterized by the replacement of normal squamous epithelium with abnormal columner epithelium. This change in tissue structure is clinically important not only as an indication of severe reflux, but the appearance of columner epithelium in the esophagus is indicative of cancer.
Current methods to treat gastroesophageal reflux disease consist of lifestyle changes such as weight loss, avoidance of certain foods that exacerbate the symptoms of GERD and avoidance of excessive bending. Elevation of the head of the bed helps prevent nocturnal reflux. While these avoidance strategies may be helpful, there is relatively little data supporting the efficacy of lifestyle modification alone for the treatment of GERD.
Medications for the treatment of GERD have been administered for years with little or no success. Conventional antacids, such as TUMS(copyright) and ROLAIDS(copyright), produce short-term relief, but often have side effects including diarrhea and constipation. H2 receptor antagonists, such as Cimetidine and Ranitidine, are relatively more effective in controlling GERD symptoms but these symptomatic therapies fail to treat the underlying cause of the disease. More powerful secretory inhibitors, such as the proton pump inhibitors Omeprazole and Lansoprazole are more effective than the H2 antagonists but these drugs are expensive and, in the long term, produce negative side effects.
Surgery has become an attractive alternative for the treatment of GERD when lifestyle modification and medications fail to treat this debilitating condition. There are numerous reflux operations available which perhaps reflect the inadequacy of any one procedure to totally control the problem. The most commonly performed operation, Nissen Fundoplication, has been effective, but is often complicated by stricture formation or gas bloat syndrome. A laparoscopic Nissen procedure has also been developed, adding another dimension of difficulty, and long-term results remain questionable. In addition, a percutaneous laparoscopic technique has been developed. (See, for example, U.S. Pat. No. 5,006,106 to Angelchik). Minimally invasive techniques, such as transesophageal implantation of a prosthetic valve have also been attempted. (See, for example, U.S. Pat. No. 4,846,836 to Reich). Despite extensive attempts in the field to treat and prevent GERD, existing forms of treatment all have shortcomings.
In view of the foregoing, and notwithstanding the various efforts exemplified in the prior art, there remains a need for a minimally invasive bulking prosthesis and deployment methodology for transesophageal delivery into the vicinity of the lower esophageal sphincter.
In accordance with one aspect of the present invention, there is provided a method of treating gastroesophageal reflux disease. The method comprises the steps of identifying a patient having gastroesophageal reflux disease, and introducing a tubular body through the mucosa in the vicinity of the patient""s lower esophageal sphincter. A fluid is injected through the tubular body to create a pocket below the mucosa, and at least one expandable bulking device is implanted into the pocket.
Preferably, the implanting step comprises deploying at least one expandable bulking device. The expandable bulking device may comprise a hydrogel. The hydrogel has an expansion ratio of at least about 100%. The hydrogel may be provided in the form of a rod, having a expanded length within the range of from about 0.5 cm to about 5 cm, and an expanded cross-sectional dimension within the range of from about 0.2 cm to about 2 cm. In one application, the method further comprises the step of explanting the esophageal bulking device from the vicinity of the lower esophageal sphincter.
In accordance with another aspect of the present invention, there is provided a method of treating gastroesophageal reflux disease. The method comprises the steps of providing an esophageal bulking device comprising an expandable hydrogel having a predetermined form, and inserting the gastroesophageal bulking device below the mucosa in the vicinity of the lower esophageal sphincter. Preferably, the bulking device has a predetermined form both before and after expansion.
The inserting step may comprise inserting two or more bulking devices. The bulking device may comprise an expandable hydrogel rod. Preferably, the bulking device has a length to thickness ratio of no more than about 15:1.
In variations of the method, the method may further comprise the step of injecting a volume of fluid below the mucosa to create a pocket prior to the inserting step. The method may further comprise the step of explanting the esophageal bulking device from the vicinity of the lower esophageal sphincter.
In accordance with another aspect of the present invention, there is provided a method of treating gastroesophageal reflux disease. The method comprises the steps of identifying a patient having symptoms of gastroesophageal reflux disease, and selecting an expandable hydrogel submucosal esophageal bulking device to treat the symptoms. The gastroesophageal bulking device is thereafter submucosally inserted in the vicinity of the lower esophageal sphincter. Preferably, the cross-sectional area of the expanded gastroesophageal bulking device is selected to compensate for deficiency in the intraesophageal closing pressure achieved by the gastroesophageal sphincter.
In accordance with a further aspect of the present invention, there is provided an esophageal bulking device for implantation below the mucosa in the vicinity of the lower esophageal sphincter, comprising an expandable hydrogel rod. Preferably, the bulking device has an expansion ratio of at least about 100%. The rod has an expanded length within the range of from about 0.5 cm to about 5 cm, and an expanded cross-section within the range of from about 0.2 cm to about 2 cm.
Further features and advantages of the present invention will become apparent to those of skill in the art in view of the detailed description of preferred embodiments which follows, when considered together with the attached drawings and claims.